P-68

Genomic components of P elements in the Australian populations of Drosophila melanogaster.

Masanobu Itoh1,2, Ian A. Boussy1, and Ronny C. Woodruff3

�i1: Dept. of Biology, Loyola University of Chicago, 2: Dept. of Applied Biology, Kyoto Institute of Technology, 3: Dept. of Biological Sciences, Bowling Green State University �j

We studied the genomic complements of P transposable elements in Australian natural populations of Drosophila melanogaster. From 45 localities in eastern Australia, 293 isofemale line were collected in 1991-1994. We digested the genomic DNAs with DdeI and probed with a short P element probe. The results demonstrated that P elements were present in many copies in all genomes examined. Full-size P and KP element classes accounted for the vast majority of P elements in all lines. The SR elements, described as having strong repressor ability and hypothesized to be important determinants of repressor function in wild populations, were very few, regardless of repressor ability. We also evaluated the lines using gonadal dysgenesis and/or singed-weak hypermutability assays. The results indicated that the latitudinal cline in P element-associated characteristics seen in 1986 had decayed. Both P activity and P susceptibility have declined, with all populations showing a tendency towards a state with little P activity potential but with P repressor function (thus Q).